Stuck in the rental market because you can't afford to get out

I'm a middle-class income, single person, but even with a good job, after I pay my rent and all my other expenses, I have nothing left over to save for a down payment on a house. I've considered trying to find a roommate to help cut costs, but because I work from home and need a dedicated office space, I would need to move to a three-bedroom unit. With the costs of rent, even with a roommate I'm basically going to be paying the same amount I am now. Plus I'd have to hope they too don't need a second room for work. How is one supposed to get out of the rental market when they can't afford to save up for a house? I've spoken to people who have said their mortgage, insurance and taxes combined are less than my current rent so if I could get a house I would be able to save and do so much more, but I can't because I can't save for the down payment.